SI4704-D60-GUR Datasheet, PDF (26/39 Pages) Silicon Laboratories – BROADCAST FM RADIO RECEIVER WITH RDS/RBDS

Si4704/05-D60
4.17. GPO Outputs
The Si4704/05-D60 provides three general-purpose
output pins. The GPO pins can be configured to output
a constant low, constant high, or high-impedance. The
GPO pins can be reconfigured as specialized functions.
4.18. Firmware Upgrades
The Si4704/05-D60 contains on-chip program RAM to
accommodate minor changes to the firmware. This
allows Silicon Labs to provide future firmware updates
to optimize the characteristics of new radio designs and
those already deployed in the field.
4.19. Reset, Powerup, and Powerdown
Setting the RST pin low will disable analog and digital
circuitry, reset the registers to their default settings, and
disable the bus. Setting the RST pin high will bring the
device out of reset.
The Si4704/05-D60 contains an on-board non-volatile
memory for storing its operational firmware. Proper
timing as specified in this data sheet, particularly with
respect to keeping RST pin low during any power
supply transitions, must be honored to avoid the risk of
corrupting the contents of this memory, which can
render the device permanently non-functional.
A powerdown mode is available to reduce power
consumption when the part is idle. Putting the device in
powerdown mode will disable analog and digital circuitry
while keeping the bus active.
4.21. Programming with Commands
To ease development time and offer maximum
customization, the Si4704/05-D60 provides a simple yet
powerful software interface to program the receiver. The
device is programmed using commands, arguments,
properties, and responses.
To perform an action, the user writes a command byte
and associated arguments, causing the chip to execute
the given command. Commands control an action such
as powerup the device, shut down the device, or tune to
a station. Arguments are specific to a given command
and are used to modify the command.
Properties are a special command argument used to
modify the default chip operation and are generally
configured immediately after powerup. Examples of
properties are de-emphasis level, RSSI seek threshold,
and soft mute attenuation threshold.
Responses provide the user information and are
echoed after a command and associated arguments are
issued. All commands provide a 1-byte status update,
indicating interrupt and clear-to-send status information.
For a detailed description of the commands and
properties for the Si4704/05-D60, see “AN332: Si47xx
Programming Guide.”
4.20. 2 V Operation (SSOP Only)
The Si4704/05-D60 is capable of operating down to 2 V
as the battery drains in an application. Any power-up or
reset is not guaranteed to work below the dc
characteristics defined in Table 2. This capability
enables a much longer run time in battery operated
devices.
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Rev. 1.2